Pieris rapae is a pest that causes serious damage to vegetables. It feeds on the leaves of plants. In severe cases, the leaves can be exposed to light, leaving only the veins or petioles. In addition, the wounds caused by cabbage caterpillars are susceptible to the invasion of soft rot pathogens and cause disease epidemics. There were two peaks of damage in the first year of the cabbage caterpillar. In the spring, with the increase of temperature, the population of the insect population rose rapidly and peaked between spring and summer. The population density of the insect population rapidly declined in the summer or rainy season, and rose again in the autumn. Due to the extensive use of chemical pesticides for a long time, many natural enemies have been killed. The resistance of cabbage caterpillars is so strong that they have to increase the amount and frequency of use of drugs and form a vicious circle, causing a large amount of pesticide residues in vegetables and directly affecting human health. In fact, vegetables There are many types of natural enemies of the worm, and there are more than 20 kinds of parasitoids only, which have great control over their population. Some special methods can also prevent and control cabbage caterpillars. Through comprehensive prevention and control, appropriate chemical pesticides can be fully implemented. Control the harm of cabbage caterpillars and produce pollution-free vegetables. Control measures 1 Biological pesticide BT insecticide 250 g per acre diluted 200 times sprayed with water. 2 Use a prophylactic pesticide 20% diflubenzuron 1 or 25% diflubenzuron 3 1000-2000 times spray. 3 Use 0.20% cabbage worm fluid solution. The method is: pick 100 grams of cabbage caterpillar per mu, smash and rot, 250 ml of water, add 50 grams of detergent, and spray 50 kg of water. The effect of prevention and cure can reach 90%. 4 Use of calcium superphosphate and lime water to prevent cabbage caterpillars, with 1% -3% of lime water or 1% -3% of superphosphate soaking spray, can avoid eggs 52% in 1 week, the first 5 days The effect can reach 84%. 5 Plant sources control Pieris rapae, use 50% bitter root bark powder, wrap with gauze, shake on vegetable strains, use 1.50 kilograms per acre, use once at the peak of egg hatching, can effectively control the damage of Pieris rapae. 6 Artificial extermination, winter picking up vegetable fields within 20 meters around the masonry and cabbage caterpillars on the building, in the spring, summer and autumn, kill cabbage Pieris larvae and larvae on the cabbage leaves, clean the pastoral after harvest. 7 Protect natural enemies, such as spiders and ladybugs, and artificially release gold butterfly wasps. China Agricultural Network Editor
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